8/19/2013
1
Topic 21: Communities
� What is a community?
� What are some examples?
� What are some measures of community structure?
� What forces shape community structure?
What is a community?
� The group of all species living at a ________________ and potentially _________________ with one another
� Defined by its _______________ features
� Includes all species, including plants and animals
www.stoys.com
� Includes more
than can be
studied
� Considers
processes and patterns above
the __________
__________
What is a community?
� ____________________
� The species that are studied
� A subset of a community
� Often restricted in terms of:
� ___________ of species
� ___________ of species
� Gives a partial picture of
what is going on
� Our focus here will be community-level processes with herp examples
� Consider the herps that live in a given locality
Haekel, Batrachia
What are some examples of
a herp species assemblage?
� Area just east of Tucson, Aizona� A diverse herp community
� Species (partial list)� Urosaurus ornatus
� Uta stansburiana
� Sceloporus clarkii
� Sceloporus magister
� Sceloporus undulatus
� Cophosaurus texanus
� Phrynosoma solare
� Aspidoscelis sonorense
� Elgaria kingi?
� Crotalus atrox
� Crotalus molossus
� Pituophis catenifer
� Masticophis bilineatus
Photos PJB
Phrynosomatinae
Serpentes
8/19/2013
2
� Yuma, SW Arizona
� Hotter, drier, lower than
Tucson
� Species (partial list)
� Sceloporus magister
� Sceloporus undulatus
� Callisaurus draconoides
� Uma notata
� Phrynosoma mcallii
� Phrynosoma platyrhinos
� Dipsosaurus dorsalis
� Gambelia wislizeni
� Coleonyx variegatus
� Crotalus atrox
� Crotalus cerastes
� Chionactis occipitalis
� Masticophis flagellumPhotos PJB
What are some examples of
a herp species assemblage?
Phrynosomatinae
Serpentes
� Osa Peninsula, Costa Rica
� Anolis polylepis
� Anolis capito
� Basiliscus basiliscus
� Ctenosaura similis
� Coniophanes fissidens
� Ameiva quadrilineata
� Sphenomorphus cherriei
� Immantodes inornatus
� Bothriechis schlageli
� Leptodactylus pentadactylus
� Eleutherodactylus spp.
� Agalychnis callidryas
� Phrynohyas venulosa
� Hyla rosenbergi
Photos: KP Bergmann; M Fogden; K Warkentin
Anura
Squamata
What are some examples of
a herp species assemblage?
� Communities can differ between localities in a region
� Different species ________________________________
� Example below: Local snakes
Valley bottom riparian(mesquite dominant)
Mountain canyon riparian(ash dominant)
Thamnophis marcianus Thamnophis cyrtopsisMasticophis flagellum Masticophis bilineatusCrotalus scutulatus Crotalus molossus
Photos: PJB; W Wells; T Brennan;
What are some examples of a herp
species assemblage? How do we measure community structure?
� _____________________
� Number of species in a
community
� One measure of diversity
� Also consider morphological,
functional & ecological
diversity
Lanier et al. 2013
� ______________________
� Which species are at a
locality
� How do they differ from another locality?
� How closely related to one
another are they
8/19/2013
1
� ____________________
� Relative abundance
� Also called species evenness
� Which species are dominant in a community?
� Which species are rare?
� ____________________
� Which niches do the different species fill?
� What are they doing in the community?
Haekel, Lacertilia
How do we measure community structure?
What forces shape community structure?
8/19/2013
1
0
20
40
60
80
100
120
140
160
180
200
0 10 20 30 40 50
Latitude
# of Species
0
10
20
30
40
50
60
70
80
90
100
Anura
Gymnophiona
Urodela
Testudines
Lizards
Serpentes
# of Species
MI, USA (42)
GA, USA (32)
Guatemala (16)
Costa Rica (10)
Ecuador (0)
What forces shape community structure?
� _____________________ __________ of the species
� Environmental gradients often determine factors like ______________________� Latitudinal gradients
correlate with both
� Lower ______________
� Warmer
� More humid
� Greater species richness
� Other factors, such as biome type also play a role
Modified from Pough et al. 2004, Table 16-1
Climate & physiological tolerance
� ___________________ is important
� Higher elevations are colder
� Simulate changes in latitude
Pough et al. 2004, Fig 5-20, 16-1
� Important climatic factors for amphibians and “reptiles”� Amount of ______________
� Amount of ______________
� _________________
� Different clades like different things (Anura vs. Squamata)� This will influence
� Species richness
� Species evenness
� Species composition
Modified from Pough et al. 2004, Table 16-2
TaxonHours Sun
Precip Temp
Anura
Testudines
Lizards
Serpentes
Correlations with species richness – US & Australia
Climate & physiological tolerance Interspecific interactions
Pough et al. 2004, Fig 16-10
� What kinds of interspecific interactions are there?
� ________________
� ________________
� ________________
� How would you expect each one to influence a species or a community?� (Species richness, occurrence, abundance, niche)
� _________________
� _________________
� _________________
8/19/2013
1
Interspecific interactions
� ________________� Some species are better
competitors than others
� ___________________
� ___________________
� Thai tadpole assemblage� Different species inhabit
different parts of water column
� Forage for different things
� Can coexist
� Also temporal partitioning: some species hatch earlier than others
Pough et al. 2004, Fig 16-10
Interspecific
interactions
� _________________ complexity
� Anolis lizards partition their habitat in various ways
� _____________________ occurs on the tiny Lesser Antilles
� Some islands have 1 species
� Intermediate body size
� Larger islands have 2 species
� One species is small
� One species is large
� The species fill different niches
� There are strong phylogenetic effects
Butler and Losos 1997
Pough et al. 2004, Fig 6-6
� Anolis habitat use changes with increased _________________
� ___________________ changes with number of species
� Anolis sagrei
� Perch diversity decreases with increasing number of sympatric species
Males
Females
Photo © I Sevi
Interspecific
interactions
� ___________ can influence
� ___________
� ___________
� Changes selective pressures
� Anolis sagrei on islands with Leiocephalus carinatus
� L. c. is a terrestrial predator
� Influences habitat use and selection
Losos et al. 2006
Interspecific interactions
� _______________
� Can decrease interspecific ______________
� Can lead to some species thriving
� Newt (Notophthalmus) is a predator of various frog tadpoles
� When predation is high, the Pseudacris crucifer tadpoles are significantly larger
� Less competition for food
with other species
� May also be more resistant to predation
Pough et al. 2004, Fig 16-13
Interspecific interactions
Pough et al. 2004, Fig 16-12
� Continuing with Pseudacris example
� When newts are absent, Pseudacris is outcompeted by other species
� When newts are in high density, Pseudacris dominate the assemblage
Interspecific interactions
8/19/2013
2
History
� __________________
� Is a clade species rich or not?
� Closely related species often are more similar ecologically
� May not live in the same community due to competition
� __________________
� Are species from a clade present in the area?
� How many species from the clade?
� Which clade got there first?
Noonan & Chippindale 2006; Duellman & Pianka, 1990
Anthropogenic Effects
� Our activities __________________________
� Some species do well in anthropogenic ecosystems, others do not
Photo © S Renzl
� Urban Arizona Species� Hemidactylus turcicus
� Callisaurus draconoides
� Sceloporus undulatus
� Urosaurus ornatus
� Sceloporus magister
� Aspidoscelis sp.
� Crotalus atrox
� Rural Arizona Species
� NOT Hemidactylus turcicus
� Also Holbrookia maculata
� Sceloporus clarkii
� Masticophis spp.
� Other Crotalus
� Gopherus agassizii
� Etc.
Anthropogenic Effects
� Introduced species act as ____________ and __________ to native species
� Mongoose, goats, cats, rats, cane toad, etc.
� Islands are highly affected/vulnerable
Photos: wikipedia; Australian Gov’t
� Bufo marinus
� Introduced to E Australia ~1940
� Biological control of Cane Beetle
� Spread rapidly
� Impacts of Bufo marinus
� _________________
� Competitor
� Predator
� _________________
� Poisons native predators
� Incl. Crocodylus johnstoni
� High native anuran tadpole mortality with Bufo marinuseggs and tadpoles
Photo: M Letnic; Fig: Crossland 2000
Anthropogenic Effects